<?php

namespace Kirby\Image;

/**
 * Returns the latitude and longitude values
 * for exif location data if available
 *
 * @package   Kirby Image
 * @author    Bastian Allgeier <bastian@getkirby.com>
 * @link      https://getkirby.com
 * @copyright Bastian Allgeier GmbH
 * @license   https://opensource.org/licenses/MIT
 */
class Location
{
    /**
     * latitude
     *
     * @var float|null
     */
    protected $lat;

    /**
     * longitude
     *
     * @var float|null
     */
    protected $lng;

    /**
     * Constructor
     *
     * @param array $exif The entire exif array
     */
    public function __construct(array $exif)
    {
        if (isset($exif['GPSLatitude']) === true &&
            isset($exif['GPSLatitudeRef']) === true &&
            isset($exif['GPSLongitude']) === true &&
            isset($exif['GPSLongitudeRef']) === true
        ) {
            $this->lat = $this->gps($exif['GPSLatitude'], $exif['GPSLatitudeRef']);
            $this->lng = $this->gps($exif['GPSLongitude'], $exif['GPSLongitudeRef']);
        }
    }

    /**
     * Returns the latitude
     *
     * @return float|null
     */
    public function lat()
    {
        return $this->lat;
    }

    /**
     * Returns the longitude
     *
     * @return float|null
     */
    public function lng()
    {
        return $this->lng;
    }

    /**
     * Converts the gps coordinates
     *
     * @param string|array $coord
     * @param string $hemi
     * @return float
     */
    protected function gps($coord, string $hemi): float
    {
        $degrees = count($coord) > 0 ? $this->num($coord[0]) : 0;
        $minutes = count($coord) > 1 ? $this->num($coord[1]) : 0;
        $seconds = count($coord) > 2 ? $this->num($coord[2]) : 0;

        $hemi = strtoupper($hemi);
        $flip = ($hemi === 'W' || $hemi === 'S') ? -1 : 1;

        return $flip * ($degrees + $minutes / 60 + $seconds / 3600);
    }

    /**
     * Converts coordinates to floats
     *
     * @param string $part
     * @return float
     */
    protected function num(string $part): float
    {
        $parts = explode('/', $part);

        if (count($parts) === 1) {
            return (float)$parts[0];
        }

        return (float)($parts[0]) / (float)($parts[1]);
    }

    /**
     * Converts the object into a nicely readable array
     *
     * @return array
     */
    public function toArray(): array
    {
        return [
            'lat' => $this->lat(),
            'lng' => $this->lng()
        ];
    }

    /**
     * Echos the entire location as lat, lng
     *
     * @return string
     */
    public function __toString(): string
    {
        return trim(trim($this->lat() . ', ' . $this->lng(), ','));
    }

    /**
     * Improved `var_dump` output
     *
     * @return array
     */
    public function __debugInfo(): array
    {
        return $this->toArray();
    }
}